Haemoglobin is the protein that makes red blood corpuscles red and binds easily and reversibly with oxygen. Normal values for haemoglobin are 14−20 g/100 mL of blood in infants, 13−18 g/100 mL in adult male and 12−16 g/100 mL in adult females. Haemoglobin is made up of protein globin bound to the red haem pigment. The globin consists of four polypeptide chains-2 alpha and 2 beta. Foetal haemoglobin does not sickle even in those distined to have sickle cell anaemia, ie, haemoglobin of foetus has higher affinity of oxygen than that an adult.